The present invention relates generally to a female terminal which includes a contact leaf spring independently of a main body of the terminal. More particularly, the present invention relates to a female terminal which is constructed in such a manner as to prevent a rapid increase in the insert force required to insert a male tab into the female terminal due to deformation of the leaf spring caused when a male tab is inserted into the female terminal.
To facilitate an understanding of the present invention, a conventional female terminal will briefly be described below with reference to FIGS. 5 and 6.
FIG. 5 is a perspective view of a conventional female terminal as disclosed in a Japanese Unexamined Utility Model Publication No. 64-12383.
A female terminal 22 includes a cable connecting portion 23 on the right-hand side and an electrical contact portion 25, for receiving a male tab terminal 24, on the left-hand side as seen in the drawing. The electrical contact portion 25 is constructed such that a separate leaf spring 28 is secured to a parallelepiped-shaped terminal insert portion 27 of a main body 26 of the female terminal 22.
The leaf spring 28 includes horizontally extending flat portions 30 and 31 on opposite sides of a convexly curved spring portion 29. In addition, the leaf spring 28 includes a pair of engagement pieces 33 on the opposite sides of the flat portion 30 in the vicinity of a male tab terminal insert opening 32.
A pair of rectangular support through holes 35 are formed in the opposite side walls 34 of the terminal insert portion 27 at the lower part thereof in the vicinity of the terminal insert opening 32. The leaf spring 28 is fitted into the terminal insert portion 27 by inserting the engagement pieces 33 of the leaf spring 28 into the support holes 35 while the flat portions 30 and 31 contact a bottom wall 36 of the terminal insert portion 27.
With such a construction, as the male terminal 24 is inserted into the female terminal 23, the convexly curved spring portion 29 of the leaf spring 28 is deflected in the downward direction by depression of the forward part of the male tab terminal 24 to assume an increasingly flattened state, as shown in FIG. 6. Subsequently, each of the flat portions 30 is bent upwardly as designated by arrow A so as to pivot about a base portion 30a so as to maintain an initial bent angle .theta. which is predetermined prior to insertion of the male terminal 24. As a result, an upper corner 33a of each engagement piece 33 integrated with the flat portion 30 abuts against an upper end portion 35a of the support hole 35, causing the engagement piece 33 to experience a reaction force F. For this reason, the spring constant of the spring portion 29 is increased with the result that an insert load to be borne by the male tab terminal 24 increases rapidly in the course of inserting the male tab terminal 24, as shown in FIG. 7. Consequently, there arises a drawback in that it is difficult to insert the male tab terminal.